Manufacturing of metal goods has long been an important part of our national economy and a major source of our national wealth. As competition from a global economy pressures our manufacturing base, it becomes extremely important that metal working machines be improved in productivity, accuracy and quality of work produced. One such group of machines are metal brakes, coper notchers, and particularly, shears. At present, sheet metal shears, although adequate in most respects, are difficult with regard to accuracy of cut. These machines consist primarily of two knives, one movable and one stationary. In most cases the lower knife is stationary and the upper knife is moved up and down. In order to accommodate materials of different thickness, there must be a considerable amount of space between the two knives while the machine is at rest. In order to minimize the force needed to make the cut, the upper, moving knife must have a cutting surface that is at an angle, called a rake angle, with respect to the lower, stationary knife. These factors leave the operator with no way to align the cut other than viewing and aligning with the edge of the lower knife. Often the plate is as wide as the bottom blade leaving it totally hidden. The cutting line on which the stock is to be sheared is, of course, drawn on the top surface of the stock. It is not possible for the operator to look straight down at the stock being sheared as the knives are recessed within the machine for safety and other purposes, therefore the operator must guess at the proper alignment. As thickness of stock being sheared increases, the difficulty of alignment increases. The result is lost work time and ruined material, decreasing the quality of work and the efficiency with which it is done. The manufacturer is left with a great need for a more efficient method of alignment. The present invention fulfills this need by providing a tool by which the desired line of cut by a sheet metal shear or similar device can easily and accurately be obtained.